It was determined that a total-flooding carbon dioxide suppression system installed in a process room requires an overpressurization vent. The system will flow 156 pounds of carbon dioxide per minute, and the enclosure strength has been calculated to be 9 lb/ft2 (71 kg). What is the minimum vent size recommended for this application?
In a total-flooding carbon dioxide suppression system, the required vent size is calculated to account for the overpressure that could develop due to the rapid release of gas. Given the flow rate of 156 pounds of carbon dioxide per minute and the enclosure strength of 9 lb/ft², we need to ensure that the vent is large enough to handle the flow without exceeding the pressure limits of the enclosure. Based on common engineering practice, a higher vent size than calculated is generally safer to ensure adequate pressure relief. Among the provided options, 50 in² (323 cm²) is the most appropriate choice as it provides a sufficient margin of safety for the given conditions.
To calculate the minimum vent size, we need to consider the flow rate of carbon dioxide and the strength of the enclosure. First, let's convert the enclosure strength from pounds per square foot (lb/ft²) to pounds per minute (lb/min) to match the flow rate of carbon dioxide. 9 lb/ft² * (156 lb/min) = 1404 lb/min Now, we compare the flow rate of carbon dioxide (156 lb/min) to the strength of the enclosure (1404 lb/min). The higher value, which is 1404 lb/min, represents the required vent size. Now, we convert this value to square inches: 1404 lb/min ÷ 30 in/min (since 1 lb/min equals about 30 in² of vent area) ≈ 47 in² So, the minimum vent size recommended for this application would be closest to option: C. 45 in² (290 cm²)
The Answer is B
The answer is B - 40 in2